> Is it possible to add dimensions and angles of a model, as in
> sketchup, by adding a script?

Sorry no, that's not really feasible for a script. Scripts can do things like automate existing functionality but dimensions are something that need need low level support in the draw engine, they're not like just automating and repackaging existing functionality like a script can usually do.

So it's not really something that can be added by a script, it needs to be added more directly into some of the core MoI modules.

> And alas we can't use the Helpers lines for align because of the second click !
Any helper lines can be created immediately after starting script but before first click defining location of dimension arrow head #1.